SAN DIEGO -- Padres third-base coach Matt Williams has been diagnosed with colon cancer and will take a leave of absence from the club beginning Friday, when he is scheduled to undergo surgery.

Williams, who is entering his second season with the team, spoke Wednesday and said he's experiencing no symptoms. He will be on hand for Opening Day on Thursday, but, understandably, wouldn't put a timeframe on his potential return.

Mike Shildt, an advisor with the team, will serve as third-base coach in Williams' absence.

Williams said the cancer was discovered as the result of routine blood work earlier this spring. He continued coaching, but recently informed the team he would step away, though he will remain in San Diego for the procedure and recovery.

"It's a strange thing, because I wouldn't have known otherwise," Williams said. "I feel as good as I've felt in 20 years, able to continue to still do my job and everything else.

"It's just a question of: It's there, and we have to go get it. So now we start that process."

Said Padres manager Bob Melvin: "He might be the toughest guy that I've ever come across in baseball. I know in particular that he's going to give this the fiercest fight of his life, and he's going to beat it."

Williams, a five-time All-Star third baseman primarily with the Giants and D-backs, joined the Padres staff upon Melvin's arrival in San Diego last season. Williams had previously served as manager of the Nationals and a coach with the D-backs and A's.

Upon his diagnosis, Williams remained with the team for the majority of the spring, though he recently ceded third-base duties to Shildt. He says he's been blown away by the support he’s received in the organization.

"It's been incredible," Williams said. "Starting with Bob and the staff, the players, [general manager A.J. Preller] and [assistant GM Josh Stein] upstairs. They just let me know that they're all with me. It's been phenomenal."

Shildt, the former St. Louis manager, has experience as third-base coach from his time in the Cardinals system. He also filled in for Williams briefly last season while Williams recovered from hip surgery.